Disaster preparedness is an essential part of the daily hospital operations particularly emergency departments (ED). The increasing threats of mass casualty incidents (MCI), makes it imperative that staff be prepared to participate in all-hazard responses. This project evaluated the effect of training and in-service on the 15'TIL 50 MCI plan, disaster supplies, and emergency operations plan on a rural hospital's ED staffs' willingness to participate in an MCI. Pre-and post-intervention surveys were used to measure outcomes, and Mann-Whitney U test, Spearman's Rank-Order Correlation Analysis, and descriptive statistics were used to evaluate data. Willingness to participate in an MCI response in one month did not change from before the intervention (Mdn = 2.50) than after (Mdn = 2.00), U = 1339, p < 0.05. Staff perceived to be significantly more confident in their level of preparedness after the training (Mdn = 3.00) than before (Mdn = 4.00), U = 1056, p < 0.05. There was significant correlation between willingness to participate and staff perception of how well the education meets their needs r[subscript s] (44) = 0.429, p = 0.004, r[superscript 2] = 0.18. Willingness to participate was significantly related with staff perception of the effectiveness of the new educational intervention r[subscript s] (44) = 0.443, p = 0.003, r[superscript 2] = 0.20. The project included a live drill in which the ED staff received and treated fifty casualties from a simulated MCI within twenty-two minutes of notification and activation only seven minutes over the required time. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]